Relay method and relay device
Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.
1. A base station apparatus comprising:
modulation circuitry which, in operation, generates, based on a control signal slot by slot, a first modulation signal s 1 and a second modulation signal s 2 as two signals or a third modulation signal s 3 as one signal,
the control signal includes one of a first transmission scheme, a second transmission scheme, and a third transmission scheme,
the first transmission scheme being for generating a first transmission signal z 1 and a second transmission signal z 2 by performing precoding on the first modulation signal s 1 and the second modulation signal s 2 respectively using a precoding matrix, and transmitting the control signal, the first transmission signal z 1 , and the second transmission signal z 2 from two antennas, the precoding matrix being selected from among a plurality of precoding matrices by regularly hopping between the precoding matrices slot by slot,
the second transmission scheme being for generating a third transmission signal z 3 and a fourth transmission signal z 4 by performing precoding on the first modulation signal s 1 and the second modulation signal s 2 respectively using a precoding matrix, and transmitting the control signal, the third transmission signal z 3 , and the fourth transmission signal z 4 from two antennas, the precoding matrix being determined from among the plurality of precoding matrices, and
the third transmission scheme being for transmitting the third modulation signal s 3 as a fifth transmission signal z 5 from one or more antennas;
transmission signal generation circuitry which, in operation,
according to the first transmission scheme,
generates the first transmission signal z 1 and the second transmission signal z 2 from the first modulation signal s 1 and the second modulation signal s 2 respectively using the selected precoding matrix,
according to the second transmission scheme, and
generates the third transmission signal z 3 and the fourth transmission signal z 4 from the first modulation signal s 1 and the second modulation signal s 2 respectively using the determined precoding matrix,
according to the third transmission scheme,
generates the fifth transmission signal z 5 from the third modulation signal s 3 ; and
transmission circuitry which, in operation,
according to the first transmission scheme,
transmits the control signal, the first transmission signal z 1 , and the second transmission signal z 2 from two antennas,
according to the second transmission scheme,
transmits the control signal, the third transmission signal z 3 , and the fourth transmission signal z 4 from the two antennas, and
according to the third transmission scheme,
transmits the control signal and the fifth transmission signal z 5 from the one or more antennas.
2. The base station apparatus of claim 1 , wherein
the control signal includes:
one or more bits indicating information on use of the two antennas and the one or more antennas; and
one or more bits indicating information on the selected precoding matrix and the determined precoding matrix.
3. A communication method for use in a base station apparatus, the communication method comprising:
generating, based on a control signal slot by slot, a first modulation signal s 1 and a second modulation signal s 2 as two signals or a third modulation signal s 3 as one signal;
generating two transmission signals from the two signals or one transmission signal from the one signal;
transmitting the two transmission signals from two antennas or the one transmission signal from one or more antennas;
the control signal includes one of a first transmission scheme, a second transmission scheme, and a third transmission scheme,
the first transmission scheme being for generating a first transmission signal z 1 and a second transmission signal z 2 by performing precoding on the first modulation signal s 1 and the second modulation signal s 2 respectively using a precoding matrix, and transmitting the control signal, the first transmission signal z 1 , and the second transmission signal z 2 from two antennas, the precoding matrix being selected from among a plurality of precoding matrices by regularly hopping between the precoding matrices slot by slot,
the second transmission scheme being for generating a third transmission signal z 3 and a fourth transmission signal z 4 by performing precoding on the first modulation signal s 1 and the second modulation signal s 2 respectively using a precoding matrix, and transmitting the control signal, the third transmission signal z 3 , and the fourth transmission signal z 4 from two antennas, the precoding matrix being determined from among the plurality of precoding matrices, and
the third transmission scheme being for transmitting the third modulation signal s 3 as a fifth transmission signal z 5 from one or more antennas;
according to the first transmission scheme,
generating, as the two transmission signals, the first transmission signal z 1 and the second transmission signal z 2 from the first modulation signal s 1 and the second modulation signal s 2 respectively using the selected precoding matrix, and
transmitting the control signal, the first transmission signal z 1 , and the second transmission signal z 2 from two antennas,
according to the second transmission scheme,
generates, as the two transmission signals, the third transmission signal z 3 and the fourth transmission signal z 4 from the first modulation signal s 1 and the second modulation signal s 2 respectively using the determined precoding matrix, and
transmitting the control signal, the third transmission signal z 3 , and the fourth transmission signal z 4 from the two antennas, and
according to the third transmission scheme,
generating, as the one signal, the fifth transmission signal z 5 from the third modulation signal s 3 , and
transmitting the control signal and the fifth transmission signal z 5 from the one or more antennas.
4. The communication method of claim 3 , wherein
the control signal includes:
one or more bits indicating information on use of the two antennas and the one or more antennas; and
one or more bits indicating information on the selected precoding matrix and the determined precoding matrix.